Upholstered seating furniture

ABSTRACT

This invention relates to upholstered seating furniture which comprises a unit of upholstered seating furniture which includes a plurality of framing elements made from rigid foam and a plurality of upholstering elements made from soft foam wherein the improvement comprises at least one opening defined in at least some of the framing elements, the surface of rigid foam around said opening being in a compressed condition, a layer of semi-rigid foam at least partly covering at least one framing element, said semi-rigid foam serving as both a base for the seat and back and as a resilient base for soft foam in other parts of said unit.

United States Patent Von Rudgisch 51 June 13, 1972 UPHOLSTERED SEATING FURNITURE [21] Appl. No.: 46,064

3,083,056 3/1963 Ward ..297/DIG. 2 3,302,276 2/1967 Williams ct al. .....297/452 X 3,534,129 10/1970 Bartel ..297/452 X FOREIGN PATENTS OR APPLICATIONS 926,720 5/1963 Great Britain ..297/DlG. 1 1,311,302 10/1962 France ..297/440 Primary Examiner-Paul R. Gilliam AttorneyBums, Doane, Benedict, Swecker 84 Mathis 57 ABSTRACT This invention relates to upholstered seating furniture which comprises a unit of upholstered seating furniture which includes a plurality of framing elements made from rigid foam and a plurality of upholstering elements made from soft foam wherein the improvement comprises at least one opening defined in at least some of the framing elements, the surface of rigid foam around said opening being in a compressed condition, a layer of semi-rigid foam at least partly covering at least one framing element, said semi-rigid foam serving as both a base for the seat and back and as a resilient base for soft foam in other parts of said unit.

10 Claims, 44 Drawing Figures PATENTEDJUN 13 we sum 01 or 10 PATENTEDJUN 1 3 1972 saw on or 10 PATENTEDJun 13 1972 saw as or 10 IJIIrH I 1 q I mmmmz A 3.669.495

saw 050F10 PATENTEDJUM? 1972 3,669,495

sum 07 or 10 PATENTED UN I972 3,669,495

sum 10 0F 10 PIC-3.43

UPHOLSTERED SEATING FURNITURE The present invention relates to upholstered seating fumiture such as armchairs, sofas, benches or the like. In conventional technology, seating furniture comprises a frame made from wood, and upholstery made from natural or synthetic materials, which are covered with a covering material such as a textile fabric, a plastics material or the like.

It is known to manufacture upholstered seating furniture from synthetic material. For this purpose, the seat frame is made from rigid foam support elements and the upholstery from a soft foam. Swiss Pat. Specification No. 464,509 discloses foam raw materials and describes how foams of different hardness can be foamed individually and how they may also be foamed one on top of the other. The physical properties of the plastics material foam used, such as hardness, softness, and resilience, may be selected so that the elements made from plastics material foam perform a framing or upholstering function.

Plastics material foams having the necessary stable shape, resistance to ageing, and permanent resilience required for this purpose are available. Such plastics material foams include foams based on polyurethane, polystyrene, polyvinyl chloride, urea formaldehyde, phenol formaldehyde, and latex etc.

In recent times, increasing demands have been made in the upholstered furniture industry with respect to reducing the manufacturing times, simplifying the manufacturing work, and designing seating furniture so that a large number of different types of furniture may be constructed from only a few basic elements. A large number of designs are possible in the case of an upholstered armchair for example. The side panels or the back, for example, have to be of different construction according to the style in which the armchair is to be constructed, while the seat for example, remains the same.

The present invention seeks to simplify the manufacture of such upholstered seating furniture both with regard to the manufacture of the separate framing and upholstery elements and the assembly thereof, and also with regard to storage by the manufacturer.

In accordance with the present invention, the basic prerequisite is for the framing elements, made from rigid foam, to be in the form of prefabricated parts such as seats, backs, side panels, scrolls, head rests, wings, etc. which may be assembled to form seating furniture. Thus, the framing elements are manufactured in the form of basic units of different shapes according to the style of the seating furniture required which are then assembled in any desired combination to form the seat.

In conventional technology, straps, spring cores, steel springs, upholstery made from synthetic or natural material, for example, are used for seating furniture springing. ln accordance with one aspect of the present invention, the seat bolsters or cushions are made exclusively from plastics material foams in a manner known per se. In accordance with another aspect of the invention, layers of semi-rigid foam are foamed onto the framing elements which are made from rigid foam.

A feature of this aspect of the invention is that the foamed semi-rigid foam serves to connect the rigid foam elements in addition to providing the upholstery. From the viewpoint of manufacturing technique, this has the great advantage that the foaming operation not only serves to form the upholstery, but at the same time replaces a connecting operation. It is not essential for the connection to be rigid, since it may be somewhat elastic and resilient, thus providing a certain degree of flexibility in the connection between the elements made from rigid foam.

In accordance with a further aspect of the invention, one way of connecting the rigid foam elements together is by providing the abutting surfaces of the rigid foam elements with grooves the open ends of which are adjacent to each other, the semi-rigid foam entering these grooves during the foaming operation, thus forming connection elements.

Advantageously, the cross section of these grooves narrows towards their open sides. The grooves in two rigid foam elements to be connected together are arranged so that their narrow sides lie adjacent. The semi-rigid foam enters the grooves and forms a connection element which corresponds to the shape of the two adjacent grooves and is therefore wider towards the outside. Thus, the connection element is retained in the two grooves, which are substantially dovetail-shaped, and cannot slip out.

In a preferred embodiment, the grooves have a circular cross sectional shape, a segment being cut from the open side of the circle thus providing the narrowing. The grooves are provided by inserting a core or an insert into the mould in which the rigid foam element is foamed. The cores or inserts may be or particularly simple construction if, in accordance with the invention, the grooves have a circular configuration, a segment being cut from one side thereof. The core or the insert is then in the form of a simple cylindrical tubular piece flattened on one side.

In accordance with the invention, the semi-rigid foam is foamed onto the rigid foam elements so as to form a resilient or cushioning, connecting element. To ensure that the semirigid foam is bonded unreleasably to the hard foam elements, and in accordance with the present invention, the outer surfaces of the rigid foam elements are provided with grooves into which the semi-rigid foam runs when it is being foamed onto the rigid foam elements, thus securing the former to the latter.

The strength of the rigid foam elements depends upon the density of the foam materials. This density is dependent upon the quantity of raw material used per unit of volume. The density and thus the strength of the rigid foam element is increased if the same quantity of raw material is used for a smaller volume. In accordance with the invention, the rigid foam elements are provided with openings in order to utilize this advantageous effect.

During the foaming operation, the surface of the rigid foam is compressed on the surfaces adjacent the openings and forms the so-called integral foam. The strength and thus the moment of resistance of the integral foam is greater than the strength and the moment of resistance of the rigid foam in the other regions of the rigid foam elements. This is due to the fact that the propellent forms the foam from the center of the mould and propels it outwardly. The foaming pressure attains its maximum on the outside, i.e. on the outsides or surfaces of the element. The separate pores in the foam are greatly compressed, and the resulting density can be ten times the density in the core or in the center of the element. Thus, by virtue of the openings providing in accordance with the invention, additional surfaces are provided artificially on which the integral foam is formed.

However, the openings have a further advantage in addition to leading to a higher surface and thus to integral foam of greater strength. The same quantity of raw material is distributed to a smaller volume when openings are provided, since the openings remain free. Thus, the same quantity of raw material is compressed to a smaller volume. Thus, the density is increased. The strength, which is proportional to the density, also increases.

The greater density and the greater strength provided by the openings can attain values which are not required. This leads to a saving of raw material. The smaller volume can be completely filled by a smaller volume of raw material. This leads to a considerable reduction in cost, since the raw material is expensive.

The following numerical example explains how a higher density and thus a higher strength may be obtained with a smaller quantity of raw material.

Let is be assumed that a volume of 15 liters is to be filled with rigid foam. A density of gr/cm is required. This requires 1.950 kg of material.

In accordance with the invention, an opening having a volume of 5 liters is provided. A residual volume of 10 liters has to be filled. If the same amount of 1.95 kg of material is introduced, this leads to a density of 195 gr/cm". This means that the density has increased by one and a half times. The strength has also increased proportionally.

An input of 1.3 kg of material is adequate if the original average density of 130 gr/cm is sufficient, thus saving 0.65 kg of raw material.

The strength has increased considerably, despite the same value for the average density. As already mentioned, the density of a foam element varies from the inside towards the outside. By providing an opening in the center of the foam element, the less dense and thus structurally weak center is removed from the element. Furthermore, additional surfaces are provided at the opening and lead to a particularly hard integral foam. The hardness of the integral foam can, for example, be up to six times the hardness of the foam in the center of the element.

By virtue of the invention, advantageous use is made of these efi'ects of the foaming operation which lead to a density which increases from the inside to the outside, and thus to increased strength, with reduced expenditure on material. Furthermore, the surfaces are increased, thus enhancing the skin formation.

In an advantageous embodiment of the invention, the corners of the openings are chamfered or extend obliquely. This simplifies the moulding. At the same time concentrations of stress, which occur in sharp corners, are considerably reduced or obviated.

Furthermore, in accordance with the invention, the walls of the openings extend obliquely. This increases the surface and thus the skin formation and strength. in the same manner, better adaptation to local stress and to the nature of the stress within the rigid foam element can be provided.

in a further embodiment of the invention, and for the same purpose, the openings do not have parallel walls, but are of irregular shape with raised ends.

Thus, the openings reduce the consumption of foam material, although greater strength is obtained since the material is compressed to a greater extent in the remaining portion and the skin formation is increased.

In comparison to wood, which is traditionally used for the framingelements of seats, the plastics material foam is advantageous in that it is easy to shape. The plastics'material foam assumes any shape prescribed by a specific shape of the mould in which the plastics material is foamed. The invention utilizes this possibility and provides shapes which simplify the assembly of the separate rigid foam elements to form the finished seating furniture and which increase the strength thereof.

in an advantageous embodiment of the invention, the abutting surfaces of the seat and back, or of the seat and the screen are stepped by forming step-like shoulders which interengage. Of course, the step-like shoulders may also be provided between other elements such as the seat and the side panels. I

In a different additional type of connection, a threaded bolt is inserted into one of the rigid foam elements which are to be connected to one another. The threaded bolt projects from the element and is screwed into a threaded plate which is inserted into the other element.

Furthermore, the abutting surfaces of the rigid foam elements to be connected to one another are provided with bores which extend at right angles to the contact surfaces and which serve for inserting connection elements such as threaded bolts. These bores are formed from the outset by appropriate inserts or cores in the mould in which the rigid foam element is foamed.

It may be necessary to provide a rigid foam element with additional reinforcement. For'this purpose, and in accordance with the invention, a metal reinforcing bar section is incorporated in the relevant rigid foam element.

Such a reinforcing bar section is incorporated in the seat for example.

In an advantageous embodiment, such a reinforcing bar section is in the form of an angle iron. Such an angle iron is arranged on each side of the seat. The angle iron extends along the side and along the rear edge of the seat. The angle iron is provided with bores which are in registry with the bores in the rigid foam element and which serve for inserting connection elements, and with bores into which the foam runs for securing purposes.

in accordance with the invention, one limb of the angle iron extends horizontally and is provided with plain or threaded bores for receiving threaded bolts holding the feet. The vertical limbs of the angle iron may be provided with threaded bores which serve for receiving threaded bolts by which the side parts and the back are mounted.

The angle iron located in the seat is bent to form an L-shape the longer limb of which extends along the side of the seat and the shorter limb of which is directed inwardly and extends along the rear edge of the seat.

If the back is also to be reinforced, a metal reinforcing bar section is incorporated in the rigid foam element forming the back.

Advantageously, this reinforcing bar section is also in the form of an angle iron, and such an angle iron is arranged on each side of the back.

In accordance with the invention, the angle irons incorporated in the back are also provided with bores which are in alignment with the bores in the seat and serve for receiving connection elements such as threaded bolts. However, further.

bores are provided and serve for inserting bolts which project from the side panels. In accordance with the invention, these latter bores are in the form of slotted holes.

Advantageously, the reinforcing bar profiles incorporated in the back are also bent to form an L the longer limb' of which extends along the side of the back and the shorter limb of which is directed inwardly and extends along the underside of the back.

The limbs extending along the underside of the back receive the connection elements, for example the bolts, which extend from the seat and which serve to connect the seat to the back.

Considerable savings in cost can be achieved by simplifying a single part which is mass-produced in the same manner as the upholstered furniture constructed in accordance with .the invention. This applies, for example, to the reinforcing bar sections which at the same time serve as metal fittings and securing elements for the threaded, screw, and inserting elements. These bar sections are arranged on both sides of the back. Further bar sections are arranged in the seat where they serve as reinforcements. The bar section arranged at the rear in the seat also forms the counter-piece for the bar sections arranged in the back and receives screws etc. The bar sections arranged in the seat are provided with further threads into which the feet are screwed.

In accordance with the invention, these bar sections and their associated threaded, screw, and inserting elements should be constructed so that they constitute mass-produced articles and can be manufactured at low cost. in accordance with the invention, this is achieved in that the bar sections are in the form of simple flat bars on which the threaded, screw and/or inserting elements are secured.

The flat bars arranged in the sides of the back have books secured thereto by welding for example, the hooks project from the sides of the back, inserting bushes are arranged in the side panels and are provided with slots which are located opposite the insides of the side panels, the hooks and the inserting bushes being located relative to each other such that they are located at the same height when the panels are in their final positions.

The inserting bushes are in the form of sleeves provided with a cavity. Vanes extend from the outside of the sleeves-in order to anchor the sleeves in the foam material.

in accordance with the invention, the hooks mounted on the flat bars on the back are provided with a sloping surface which engages behind the surface of the slots when the hooks are inserted into the inserting bushes.

If the upholstered furniture is provided with a screen, i.e. a bar or moulding mounted on the front narrow side of the seat, and side panels, smooth inserting bushes and threaded bushes in alignment with one another are formed in the seat, in the screen, and in the side panels, and bores pass through the seat, the screen, and the side panels in alignment with the bushes, screws being inserted or screwed into the bushes.

In accordance with the invention, to secure a head rest to the top of the back, hooks are arranged in the top of the back and partially project therefrom, inserting bushes co-operating with these hooks are arranged in the head rest, the head rest being slipped on to the hooks from one side and being held by side panels slipped over its ends.

To secure the feet, and in accordance with the invention, threaded bushes are let into the underside of the seat, the feet being screwable into the bushes. The sides of the bushes may be provided with vanes for the purpose of securing the bushes in the foam material.

To connect the back to the seat in a simple manner, the flat bars let into the underside of the back and into the rear of the seat are located at the same height and have bores which are in alignment with each other. The back and the seat are connected to one another by a screw inserted through the bores and secured by a nut.

In accordance with the invention, the back is especially provided with a layer of soft foam, since the back of an armchair must be softer or have a greater cushioning effect than the seat. The softness or cushioning effect must be greater at the top narrow side of the back than on its remaining surface, since this is where the seated person rests his head. In order to obtain the desired softness or cushioning effect at the top narrow side, and in accordance with the invention, the top narrow side of the back (i.e. the rigid foam element) is provided with a recess, so that the expanded layers of semi-rigid foam and soft foam attain a greater thickness at this position.

The softness and cushioning effect of the seat should be particularly great at the front edge. In accordance with the invention, this is achieved in that the front end of the seat and the top of the screen are each provided with a recess so that the foamed layers are provided with a greater thickness in the region in contact with the legs of the seated person.

There are places on the chair,sofa or the like where the softness and cushioning effect, i.e. the depth to which the surface may be depressed by the same application of force, should vary. The invention can readily fulfil these requirements. It is necessary only to expand the semi-rigid foam layers and the soft foam layers to different thicknesses in accordance with the desired softness and cushioning effect at the respective places. The different heights of the foam layers are obtained by specially designing the respective moulds.

The back and the seat of a chair, or the like, must be ventilated so that the seated person does not perspire. For this purpose, and in accordance with the invention, the semi-rigid foam layer or the soft foam layer foamed onto the seat or the back is provided with holes. The seat and the back move forwards or backwards to a greater or lesser extent at each movement of the seated person, so that air can flow through the holes.

Due the lesser density of soft foam, the quantity of raw material required for the soft foam per unit of volume is less than in the case of rigid foam. Accordingly, the cost of soft foam per unit of volume is less than in the case of semi-rigid or rigid foam. Thus, advantageously, areas which are not subject to static stress, or which are subject to only slight static stress, are padded with soft foam. Such slight static stress occurs in the center region of the back. Thus, adequate rigidity is provided if this region is filled with soft foam.

It has already been mentioned that a layer of soft foam is foamed onto the layer of semi-rigid foam on the back. In accordance with the invention, this soft foam passes through the holes in the layer of semi-rigid foam on the back during the foaming operation and runs into the interior space in the frame-like back where it forms a core of soft foam. It is also necessary to fill the back in order to provide a continuous,

smooth surface on the rear of the back for the covering material.

In accordance with the invention, the foam layers on the back, the seat, the side panels, the screen, the head rest, etc. are covered with a covering material such as a textile fabric, a plastics material, etc.

In an advantageous embodiment of the invention, the back, the seat, the side panels, the screen, the head rest etc. are provided with nailing grooves into which the ends of the covering material are inserted and secured. Advantageously, the nailing grooves are arranged at places which are covered by another part during assembly. The nailing grooves are located in the contact surfaces of the seat and the back for example.

Advantageously, the back is covered by a covering material which is sewn in the form of an envelope which is drawn over the back. This envelope is open at one end and is drawn onto the back by this open end. In accordance with the invention, the lateral narrow sides in the center of the lower region of the back are provided with recesses into which the bottom open ends of the envelope, made from the covering material, are inserted. These recesses are concealed by the side panels when the piece of furniture is in the assembled state.

Advantageously, the slotted holes which receive the inserting bolts projecting from the side panels are located within these recesses.

The recesses have an additional purpose. Some backs are of wedge-shaped construction, i.e. their thickness increases from the top to the bottom. The bottom and thus wider regions of the narrow sides of such as backs are not covered with covering material, since these regions are concealed by the side panels. Thus, covering material can be saved. If the back is covered with an envelope of covering material, the envelope will be left open in the bottom region of the narrow sides of the back in order to save material, since these places are also concealed by the sides. These open ends of the envelope are accommodated and secured in the recesses.

In order satisfactorily to connect the seat to the back, the contact areas of the seat and the back must be as large as possible. In accordance with the invention, the abutting faces of the back and the seat are oblique and have a relatively large surface. These sloping surfaces may readily be obtained by the appropriate configuration of foam moulds. Different angles between the seat and the back are obtained by varying the angle of these oblique faces relative to the horizontal.

It has already been mentioned that the seat, sofa, or the like should be particularly soft at specific places.

By way of example, and in accordance with the invention, the layer of semi-rigid foam which is foamed onto the side panels is thickened in the region in which the seated person rests his hands, so that this thickened portion forms a soft, resilient hand rest.

In accordance with the invention, the top narrow side of the back is provided, particularly at the ends, with narrow projections which serve to improve the hold of the foam-on layer of semi-rigid foam. If these projections are provided only at the ends, the center of the foamed-on layer is at the same time provided with a greater depth, so that the softness is increased in this region. Thus, the back is rendered softer at the place where a seated person rests his head.

A similar softness is also required for the tops of the narrow sides where a seated person rests his arms. To meet this requirement, and in accordance with the invention, the top narrow sides and the outsides of the side panels are provided with grooves which extend along the top edge at a short distance below the latter, and an arm pad of semi-rigid and/or soft foam is foamed onto the top barrow side and somewhat below on a top edge region of the side face, the foam having run into the grooves during the foaming-on operation for the purpose of anchoring the arm pad by forming tongues. A tongue and groove connection is produced, the tongues being integrally formed with the arm pad.

It has already been mentioned that the rigid foam elements are provided with openings at the places less subject to static stresses, in order to save material and in order to obtain greater rigidity by increased compression of the material at the other places.

Thus, in an advantageous development of the side panels, the opening provided in the side panel is divided into two openings which are located one behind the other and which are separated from one another by a rib or bridge.

In an alternative side panel, the opening provided therein is divided into two smaller openings which are located one beside the other and which merge into one another, the outer opening being larger and the inner opening being smaller.

In accordance with the invention, the back has a larger opening which is of substantially square shape and which is located in the top region of the back, two further smaller openings being provided below this larger opening.

In an advantageous design of these two smaller openings, their top, outer corners are raised or provided with projections, thus achieving the object of designing the openings so as to have the largest possible area, thus saving expensive raw material.

Experiments have shown that the openings lead to greater rigidity despite the lower expenditure on material. This results from the fact that the smaller quantity of material is compressed to a greater extent in the remaining smaller volume, greater compression automatically leading to greater rigidity.

There are various ways of shaping and mounting the wings. The invention proposes an embodiment in which the wings cover the sides of the top region of the back and the ends of the head rest mounted on the back, the semi-rigid foam forming connection elements by running into the grooves which have already been mentioned and which are provided in the abutting faces of the back, headrest and wings.

With regard to the upholstery, the back requires a different construction from the seat for example. The back should be softer than the seat for example. Furthermore, the entire surface of the back is a visible surface, while only the top of the seat is a visible surface or can be touched. Thus, in accordance with the invention, the layer of soft foam foamed onto the back advantageously surrounds the inside, the top and the outside of the back.

The invention provides different shapes for the screen. In the first embodiment, the screen extends only along the front side of the seat.

In a second embodiment, the screen extends along the front side of the seat, its ends being angled rearwardly, and partially surrounds the sides of the seat. This embodiment is used if the side panels do not reach to the front edge of the seat, but are set back towards the rear.

In a modification of this latter embodiment, the rearwardly angled ends of the screen taper in the form of sloping faces which overlap and abut against corresponding sloping faces on the front ends of the side panels.

There are some styles of furniture which require the screen to be extended downwardly almost to the ground. In this embodiment, it may be advantageous for the screen -to be used at the same time for securing the front feet which are generally secured below the seat. In accordance with the invention, this is achieved by extending the screen downwardly and providing it with a rearwardly angled bottom strip which engages below the front edge of the seat, feet such as low spherical rollers being secured on the underside of the bottom strip.

In the case of a chair, it may be necessary for the back to be of greatly resilient construction, so that it bends or tilts backwardly if the person sitting in the chair bends his back towards the rear. To meet such a requirement, and in accordance with the invention, the frame-like element of rigid foam forming the back is in the shape of a U open at the top, the height of the U being lower than the total height of the back, a tubular resilient element, which completes the upwardly open U to form a closed frame, being inserted into the top ends of the arms of the U, and the resilient element being covered with semi-rigid and/or soft foam layers to form a complete closed back. The rigid construction of the back comprising semi-rigid foam is thus partially replaced by the resilient element, so that a highly flexible or resilient back is produced.

In accordance with the invention, the resilient element comprises individual tubular pieces which are spaced one behind the other and which are covered with a soft foam which holds them together.

In accordance with the invention, these tubular pieces are provided with bores through which the foam runs into the tubular pieces. Thus, the tubular pieces are held together by the foam which has penetrated into them 'and which extends in one piece in a sausage-shaped manner through all the tubular pieces located one behind the other, and by the foam surrounding them.

The bores through which the foam runs into the tubular pieces are distributed along the tubular pieces in the longitudinal direction thereof. They pass through the walls of the tubular pieces at right angles thereto and are located opposite one another in pairs.

Advantageously, pairs of bores located behind each other are staggered by pieces, determines to extent The distance between the ends of the tubular pieces, or the gap between the tubular pieces, determines the extent to which the resilient element can be deflected. The spring action is terminated when the tubular pieces close the gap and their ends abut against one another. The soft foam located in the gap is then compressed at one side and expanded at the other side.

In the basic shape, the gaps between the ends of the tubular pieces have parallel sides. The width of the gaps then determines the spring action which may be attained.

In a modified embodiment, the gaps between the ends of the tubular pieces are wedge-shaped gaps. This means that the resilient element can be deflected to different degrees towards both sides. The tubular pieces can move closer together at the side at which the gaps are wider, thus resulting in a considerable spring action. When pressure is exerted in the opposite direction, the ends of the tubular pieces immediately abut against each other due to the slight width of the gaps, so that the spring action is slight in this direction.

It is obvious that this resilient element of the invention may also be used in furniture other'than seating furniture. For example the resilient element may be used in mattresses, cushions, floor mats for gymnasts, etc.

The invention will now be further described by way of example with reference to the accompanying drawings, in which:

FIG. 1 is an exploded illustration of a plurality of rigid foam parts which form the frame of an upholstered chair,

FIG. 2 is a exploded illustration similar to FIG. I, in which the rigid foam parts are covered with semi-rigid foam,

FIG. 3 is an exploded illustration similar to FIG. 1, of a different embodiment which includes an arm rest,

FIG. 4 is a rear elevational view of the back panel of the chair of FIG. 3,

FIG. 5 is a section through the bottom bar of the back panel taken on the lines 5-5 of FIG. 4;

FIG. 6 is a section through the side panel, taken on the line 6-6 of FIG. 3,

FIG. 7 is a perspective illustration of one form of back panel having a head rest and a wing,

FIG. 8 is a perspective illustration of a finished upholstered chain manufactured in accordance with the invention,

FIG. 9 is a section through the top bar of the back panel and through the head rest, taken on the lines 99 of FIG. 7,

FIG. 10 is a section corresponding to FIG. 9, but with semirigid foam foamed onto the rigid foam frame elements,

FIG. 11 is a section corresponding to FIG. 10), in which soft foam has additionally been foamed on,

FIG. 12 is a section through the front bar of the seat and an attached scroll,

FIG. 13 is a section similar tive scroll,

FIG. 14 is a section similar to FIG. 12, showing a further a1 temative scroll,

to FIG. 12, showing an alterna- FIG. is a plan view of the scroll illustrated in FIG, 12,

FIG. 16 is a plan view similar to FIG 15 showing a different scroll,

FIG. 17 is a plan view similar to FIG. 15 showing another scroll,

FIG. 18 is a fragmentary perspective view of the back panel and illustrates a preferred form of wing,

FIG. 19 is an ilustration similar to Hg. 18, showing an alternative wing,

FIG. 20 is a longitudinal section through an upholstered armchair manufactured in accordance with the invention,

FIG. 21 is a fragmentary plan view of the upholstered armchair illustrated in FIG. 20, showing especially the metal reinforcing profiles incorporated in the seat and the back panel,

FIG. 22 is a section through an alternative back panel,

FIG. 23 is a front elevation of the back panel illustrated in FIG. 22,

FIG. 24 is a section through an alternative seat,

FIG. 25 is a plan view of the seat illustrated in FIG. 24,

FIG. 26 is a vertical section through the connection between the seat and the back panel,

FIG. 27 is a horizontal section through the connection between the seat, side panel, and scroll,

FIG. 28 is a section through the threaded bush into which the feet are screwed,

FIG. 29 is a plan view of the bush,

FIG. 30 is a section through a smooth inserting bush,

FIG. 31 is a fragmentary view of the back panel particularly showing the inserting elements for securing the side panel,

FIG. 32 is a fragmentary section through a side panel, particularly showing the inserting element for connecting the side panel to the back panel,

FIG. 33 is a side elevation of an inserting bush,

FIG. 34 is a plan view of the bush of FIG. 33,

FIG. 35 is a diagrammatic illustration of the manner in which the head rest is secured to the back panel,

FIG. 36 is a perspective illustration of a seat and of a back panel, the frame of the back being formed partially by the resilient element constructed in accordance with the invention,

FIG. 37 is a section through a part of the resilient element constructed in accordance with the invention,

FIG. 38 is a section similar to FIG. 37, in which the resilient element is illustrated in a deflected state,

FIG. 39 is a schematic, perspective illustration of a form of the resilient element which, by virtue of wedge-shaped gaps, is provided with a spring action dependent upon direction,

FIG. 40 is a section through a part of the resilient element illustrated in FIG.39,

FIG. 41 is a section similar to FIG. 40, in which the wedgeshaped gap is closed, or the resilient element deflected,

FIG. 42 is a section taken on the line 42-42 of FIG. 40,

FIG. 43 is a section similar to FIG. 40, in which the wedgeshaped gap is narrower, and

FIG. 44 is a section through the tubular element illustrated in FIG. 43, the tubular element being in the deflected state.

FIG. 1 shows a frame-shaped back panel 42, a frame-shaped seat 44, a side panel 46, and a screen 48. These parts are made from rigid foam and constitute the framing elements of an upholstered armchair. An opening is formed in the back panel 42, an opening 52 is formed in the seat 44, and two openings 54 are provided in the side panels 46. Some comers of each opening are chamfered at 56. This reduces undesirable concentrations of stress and notch stresses. A foam groove 58 extends along the top edge of the back panel 42. A further foam groove 60 surrounds the opening 50. The bottom end of the back panel 42 is provided with a large oblique surface 62 by which the back panel 42 abuts against the seat 44. A further foam groove 64 extends along the top edge of the oblique surface 62 and an indentation 66 extends along the bottom edge of the oblique surface 62. The indentation 66 serves to improve the connection of the back panel 42 to the seat 44. The side faces of the back 42 are provided with recesses 68 into which the bottom ends of the covering material are inserted. The slotted holes 70, into which the side panels 46 are fitted, are also located in the recesses 68. Bores 72 are provided in the back 42, in the seat 44, and in the side panels 46. Connection elements such as threaded bolts or screws are inserted through these bores.

The front side of the seat 44 has a step like shoulder 82. The rear of the seat 44 is provided with an oblique surface 84 which abuts against the oblique surface 62 of the back panel 42 when the chair is in its assembled state. The rear of the seat 44 is also provided with a projection 86 which fits into the indentation 66 in the back panel 42. A foam groove 78 extends around the opening 52in the seat 44. The front bar of the seat 44 is also provided with a recess 80. The semi-rigid foam material subsequently runs into this recess to provide extra thickness. Thus, at this place, the seat 44 is softer. A recess 74 intended for the same purpose is also provided on the top of the back 42. The top of the back is also provided with two pro- 20 jections 76 which serve to improve the hold of the layer of semi-rigid foam to be foamedon.

The top of the side panel 46 is provided with grooves 88. The semi-rigid foam subsequently runs into these grooves and is held therein. The side panel is also provided with a bolt 90 which is inserted into the slotted hole 70 in the back 42. Nailing grooves 92 for nailing or stapling the covering material are provided in the side panel 46.

The scroll 48 is provided with a projection 94 which abuts against the step-shaped shoulder 82 on the seat 44. The scroll 48 is also provided with a recess 96 which is filled with semirigid foam, thus providing the desired soft support for the legs of the person seated in the armchair.

FIG. 2 shows the rigid foam elements, illustrated in FIG. 1, having the layers of semi-rigid foam foamed thereon. The inside of the back panel 42 is coated with a layer 98 of semi-rigid foam. The seat 44 is covered with a layer 100 of semi-rigid foam which at the same time forms the entire area of the seat. The scroll 48 is coated with a layer 102 of semi-rigid foam. The side panel 46 is covered by a layer 104 of semi-rigid foam. The front of the layer 104 has a thickened portion 106, thus providing a soft support for the hands. The layers 98 and 100 of semi-rigid foam are provided with holes 108. This ventilates the back and the seat and prevents a person sitting in the armchair from perspin'ng. FIG. 2 also shows how the layers of semi-rigid foam have filled the foam grooves 58, how they have covered the projections 76, how they have filled the recesses 80 and 96, and how they have run into the grooves 88.

FIG. 3 shows a head rest and two wings 112 which are not shown in FIG. 1. The faces of the back panel 42, of the head rest 110, and of the wings 112, which abut against each other when the chair is assembled, are provided with grooves 88 into which the semi-rigid foam runs for the purpose of interconnecting these parts. FIG. 3 also shows the reinforcing profiles 114 which are incorporated in the back panel 42. The reinforcing profiles 114 are provided with slotted holes 116 which are in alignment with the holes 70. The reinforcing profiles 114 are also provided with bores 118 which are in alignment with the holes 72 in the back panel.

In this embodiment of the seat 44, the from bar is provided with locating bores 120. A threaded bolt 122 is also provided. The threaded bolt 122 is associated with a bolt (FIG. 21). The locating bores receive locating pegs 124 which are formed on the scroll 48. The threaded bolt 122 is screwed into a threaded plate 126 which is incorporated into the screen 48. Similar threaded plates 128 are incorporated in the side panels 46.

FIG. 3 also shows an arm rest 130 which is made from semirigid and/or soft foam. It is provided with tongues or beads 132 which are located in the longitudinal grooves 88 in the side panel 46 when the chair is assembled. The arm rest 130 is foamed onto the side panel 46 in a mould, the tongues or beads 132 being formed in the grooves 88.

FIG. 4 is a rear view of the back panel 42. Two smaller openings 134 are provided below the large, square opening 50. The top outer comers of the openings 134 are extending upwardly and form projections 136. The projections 136 extend parallel to the chamfers 56 of the opening 50. The projections or upwardly extended ends 136 illustrate the object of the invention, which is to provide the rigid-foam elements with the largest possible number of openings in order to save material or to compress the same or smaller quantities of material to a smaller volume.

FIG. 5 shows the bottom bar of the back, as illustrated in FIG. 4. A nailing groove 65 is also shown, into which one end of the covering material is fitted.

FIG. 6 shows a section through the side panel 46 illustrated in FIG. 3. The side panel 46 is provided with two openings 138 and 140. These two openings are located laterally adjacent to each other. The inner opening 140 is smaller, since the inside of the side panel, where the seated person is located, should be closed as far as possible. However, the opening 138 on the outside of the side panel can be larger.

FIG. 7 is a perspective illustration of a back 42 having a head rest 110 and a wing 112. The special purpose of this Figure is to show, in conjunction with the sections shown in FIGS. 9 to 11, how the head rest 110 and the wing 112 are secured to the back panel 42. When the layer 98 of semi-rigid foam is foamed onto the back panel 42 (see also FIG. 2) the semi-rigid foam runsinto the grooves 88. This is shown in FIG. 10. In conformity with the configuration of the abutting grooves 88 in the back panel 42, in the head rest 110, and in the wing 112 (See FIG. 7), the semi-rigid foam in the grooves assumes the shape of a rib which has a necked-down center region and which securely connects the two rigid foam elements. Since the semi-rigid foam has a certain elasticity, the head rest 110 and the wings 112 are resiliently connected to the back panel, so that they yield slightly when pressed.

FIG. 11 shows a layer 142 of soft foam which is foamed across the entire back panel. The soft foam has passed through the holes 108 into the opening 50 in the back where it forms a core of soft foam or filling mass.

In the sections shown in FIGS. 9 to 11, and in other sectional drawings, the rigid foam elements are indicated by oblique shading, while the semi-rigid foam is cross-shaded, and the soft foam is shown by dotting.

FIGS. 12 to 14 show various scrolls 48. The scroll 48 abuts only against the front side of the seat and is provided with locating pegs 124 illustrated in FIG. 3. The rear of the scroll 48 illustrated in FIG. 13 has a stepped configuration as is illustrated in FIG. 1 and which ensures the the scroll engages better with the front bar of the seat 44. The bottom of the scroll 48 illustrated in FIG. 14 is extended downwardly and angled rearwardly, thus producing a bottom strip 144 which is located below the front bar of the seat. Spherical rollers 146 are secured below the bottom strip 144.

FIGS. 15 to 17 are plan views of various scrolls 48. The rear of the scroll 48 abuts against the front of the seat and against the front ends of the side panels 46. The scroll 48 illustrated in FIG. 16 is angled rearwardly. In this embodiment, the two side panels 46 are set back or shorter. The angled ends 148 of the scroll 48 abut against the front ends of the side panels 46.

The embodiment illustrated in FIG. 17 is based on the embodiment illustrated in FIG. 16. The side panels 46 extends further towards the front. The side panel 46 and the scroll 48 abut against each other along the sloping faces 150.

FIGS. 18 and 19 illustrate various wings 112. FIG. 18 illustrates a wing which is wider at the top than at the bottom and whose outside is of sloping configuration. FIG. 19 illustrates an elongate wing whose longer sides extend vertically.

The unit-composed system of the present invention is shown particularly clearly in FIGS. 12 to 19. Irrespective of the individual appearance of the various elements, they can be assembled in an optional manner and are always interconnected in accordance with the same system.

FIG. 20 is a section through the center of an upholstered armchair manufactured in accordance with the invention. The front and the rear bar of the seat are indicated by oblique shading. The surface of the seat is formed by a layer 100 of semi-rigid foam. A seat bolster or cushion 152 is located on the seat. A back bolster of cushion 154 is also provided. It may be seen that the seat is provided only with the layer 100 of semi-rigid foam, while the back panel 42 is provided with the layer 142 of soft foam in addition to the layer 98 of semi-rigid foam. A reinforcing member 162 is incorporated in each side of the seat and this is shown in FIG. 21. The reinforcing member holds the screws 164 which secure the side panel 46 and which are screwed into threaded plates 128 (FIG. 21). The shorter limb of the reinforcing member also holds the screws 166 which secure the back panel 42. Finally, the reinforcing member 162 holds screws 168 which in turn secure the feet 170. In accordance with the invention, the reinforcing member 162 in the seat 44 and the reinforcing member 114 in the back panel 42 are directed towards one another, so that the corresponding bores are located opposite one another and the screws or the threaded bolts can be passed therethrough. If screws, such as the screws 168, are screwed into the reinforcing members, it is advantageous to weld appropriate nuts onto the reinforcing members.

FIG. 20 shows the soft foam which has run through the holes 108, or from the rear, into the hollow center cavity in the back 42 where it forms a core 158 of soft foam. FIG. 20 also shows that the layer 142 of soft foam is thickened above the top of the back panel 42 where it forms a thickened portion 160. The thickened portion 160 is the result of the recess 74 illustrated in FIG. 1. Thus, a person sitting in the armchair can rest his head on a soft, resilient support. The same applies to the scroll 48, or to the front bar of the seat 44, where it may be seen that the layers 100 and 102 of semi-rigid foam are thickened. This results from the recesses and 96 which may I be seen in FIG. 1 and which are filled by the semi-rigid foam.

FIG. 20 also shows the covering material 172, 174, 176 which covers the back panel 42, the screen 48, and the seat 44 respectively. It may also be seen that the ends of this covering material are located in nailing grooves. In order to avoid rendering the drawing obscure, the nailing grooves are not provided with reference numerals in FIG. 20. The nailing grooves are located in the contact surfaces between the back and the seat and between the seat and the screen, so that they are concealed from the outside. In accordance with the invention, the nailing grooves are constructed so that the covering material has to pass over a plurality of sharp edges before it terminates in a nailing groove. Contact against a plurality of sharp edges occasions frictional forces which prevent the covering material from being pulled out of the nailing grooves.

Finally, it may be seen from FIG. 20 that the layers 98 and of semi-rigid foam have penetrated into the various foam grooves in the back panel 42 and the seat 44 where they are anchored. This prevents the layers of semi-rigid foam from becoming detached from the hard foam elements when under stress.

FIGS. 22 and 23 show details of an alternative form of back in which the reinforcing profiles are formed by single flat bars. A single flat bar 200 is incorporated in each side of the back 42 and serves to reinforce the back and to connect it to the side panels. In the form illustrated, two hooks 202 are mounted on each flat bar. The hooks 202 are mounted in plates or bushes 204 which are welded onto the flat bars 200. The hooks 202 are screwed into the bushes or plates 204. A hook 202 is illustrated in FIG. 31, drawn to a somewhat larger scale, where the sloping face 203 on the inside of the hook may be seen. A further flat bar 206 extends in the bottom of the back 42. Bores 208 are provided in the fiat bar 206. The bores 208 serve for receiving screws 122 which are illustrated in FIG. 26. The heads of these screws are illustrated by broken lines in FIG. 23. Bores 72 pass through the back in alignment with the bores 208.

FIGS. 24 and 25 illustrate the seat 44. A flat bar 212 serving as a reinforcement extends in the rear of the seat 44. Bores 214 pass through the flat bar 212 and the hard foam of the seat. The bores 214 are in alignment with the bores 208 in the back and serve for receiving the screw 122 illustrated in FIG. 26. The head of the screw 122 abuts against the flat bar 206. A nut 213 is screwed onto the other end of the screw 122 and abuts against the flat bar 212. Threaded bushes 210 are formed in the underside of the seat 44. The feet 170 (see for example FIG. are screwed into the threaded bushes 210. To improve the anchorage of the threaded bushes 210 in the rigid foam of the seat, the threaded bushes 210 may be provided with side projections 218 as illustrated in FIG. 28. In the same manner as the other metal fittings, the threaded bushes 210 are placed in the mould in which the rigid foam part is foamed and shape. To prevent the thread of the threaded bush 210 from being filled with foam, the threaded bush may be provided with a bottom 220 (FIG. 28).

FIG. 27 illustrates the manner in which a side panel 46 and the scroll 48 are secured to the seat 44. Bushes 216 having a smooth internal bore are located in the seat 44. Threaded bushes 222 are located in the side panel 46 and in the screen 48 opposite the bushes 216. Screws 164 are screwed into the threaded bushes 222 from the inside. The heads of the screws 164 then abut against the flanges of the bushes 216.

FIGS. 28 to 30 show the threaded bush 222 into which the feet may be screwed, and the smooth inserting bush 216.

A hook 202 secured to the flat bar 200 is illustrated in FIG. 31, although it is drawn to a larger scale than the hook illustrated in FIG. 23. The hook 202 is directed downwardly. An inserting bush 232 in the side panel 46 is located opposite the hook, as shown in FIG. 32. Details are illustrated in FIGS. 33 and 34. The inserting bush 232 has a cylindrical cavity 234. The top end of the bush has a slotted hole 236. Two flanges 238 serve to improve the anchorage of the bush in the foam material. The side panel 46 is slipped on from below. The hook 202 then engages into the slot 236. The sloping surface 203 (FIG. 31) runs on the bottom edge of the slot 236 and draws the side panel 46 securely against the back 42. The upward movement terminates when the side panel abuts against the lateral projection 240 on the back panel.

FIG. 35 shows the manner in which a head rest 110 is secured to the back panel 42. Hooks 202, having plates 204 of the kind already described, are incorporated in the top edge of the back panel 42. Inserting bushes 232 are incorporated in the head rest 1 10. The head rest 110 is slipped onto the hooks 202 by means of these bushes, in the same manner as described with reference to the side panels. In this embodiment of upholstered seating furniture having a head rest 110, side panels are used which extend upwardly beyond the seat 44 and which conceal the ends of the head rest 110. The side panels 46 are fitted after the head rest 110 has been fitted, thus laterally securing the head rest 1 10.

In the embodiment illustrated in FIG. 36, the frame-shaped back 42 is in the shape of a U. The top half of the back is formed by a resilient element 258 constructed in accordance with the invention. Details of the resilient element are shown in FIGS. 37 and 38. The resilient element comprises separate tubular pieces 260 which are located one behind the other or adjacent to each other. The tubular pieces may be made from any suitable material. In accordance with the invention, it is advisable to manufacture the tubular pieces from rigid foam. The tubular pieces 260 are provided with pairs or bores 262 located opposite one another. The pairs of bores are staggered by 90 relative to one another. Soft foam 264 enters the interior of the tubular pieces 260 through the bores 262. The gaps 266 between the tubular pieces are also filled with soft foam, thus providing a resilient element. The resilient element may be deflected in any direction, as illustrated in FIG. 38. The deflection terminates when the ends of the tubular pieces 260 abut against each other at one side. The hardness of the foam is selected in conformity with the desired resilience. In the case of the back panel 42 illustrated in FIG. 36, the entire back may be filled with soft foam, or various layers of semirigid and soft foam may be used as shown in FIG. 20.

The resilient element 258, which may also be used independently of the chair constructed in accordance with the invention, is illustrated in detail in FIGS. 39 to 44. Bends 268 are illustrated in FIG. 39. FIG. 39 also shows that the gaps between the tubular pieces do not have parallel walls, but are in the form of wedge-shaped gaps. Such a wedge-shaped gap 270 is shown particularly clearly in FIG. 40. Thus, the embodiment of the resilient element illustrated in FIG. 39 can be deflected only in the direction of the arrows. Thus, rigidity is increased when the resilient element 258 is used in a back panel 42. The resilient element can be deflected in only one direction, i.e. inwaIdly.

The resilient element illustrated in FIG. 40 is shown in its deflected state in FIG. 41. The deflection is terminated when the ends of the two tubular pieces 260 abut against one another and the wedge-shaped gap 270 has changed into a gap having parallel walls.

FIGS. 43 and 44 are similar to FIGS. 40 and 41. They illustrate the principle of the present invention by which the maximum deflection or resilience may be determined by varying the opening angle of the wedge-shaped gaps 270.

While various arrangements of seating furniture have been described in the drawings, and while various arrangements of resilient element have been described in FIGS. 36 to 44, other arrangements of seating furniture and resilient elements may be resorted to without departing from the spirit and scope of the invention as defined in the appended claims.

I claim:

1. A unit of upholstered seating furniture which includes a plurality of framing elements made from rigid foam and a plurality of upholstering elements made from soft foam wherein the improvement comprises:

at least one opening defined in at least some of the framing elements,

the surface of rigid foam around said opening being in a compressed condition,

a layer of semi-rigid foam at least partly covering at least one framing element,

said semi-rigid foam serving as both a base for the seat and back and as a resilient base for soft foam in other parts of said unit,

said openings being provided with chamfered corners thereby reducing undesirable stress concentrations,

at least a side of one of said opening and chamfered corners associated therewith extending obliquely to a surface of said framing elements, said base and back elements of said seat each having abutting oblique surfaces forming a joint surface, and at least one of said base and said back elements being tapered as to depth.

2. A unit as defined in claim 1 wherein grooves are provided on the adjacent surfaces of said rigid foam elements, the open ends of said grooves abutting against one another and having cross section which narrows towards their open sides, said semi-rigid foam running into said grooves during foaming so as to form connection elements with said rigid foam elements.

3. A unit as defined in claim 1 wherein a metal reinforcing profile is incorporated in the rigid foam element forming the seat and a metal reinforcing profile is incorporated in the rigid foam element forming the back and wherein the reinforcing profiles of the seat and the reinforcing profiles of the back include single flat bars, said bars being aligned with said joint surfaces, and including fastening means cooperating with said bars for securing said back and seat together at said joint surfaces.

4. A unit as defined in claim 1 wherein the top surface of the front end of the seat is provided with respective recesses in order to provide the foamed-on layers with a greater thickness in the region where the seated person rests his legs, said semirigid foam layer having a substantially plane top surface extending across said recesses, whereby the layers of semi-rigid foam and the layers of soft foam being formed on in varying thicknesses according to the softness and resilience required at the respective places.

5. A unit as defined in claim 1 wherein the respective layers of semi-rigid foam foamed onto the seat and the back are provided with holes for the purpose of ventilation.

6. A unit as defined in claim 1 wherein a layer of soft foam is foamed onto the layer of semi-rigid foam on the back, the soft foam flowing through the holes during the foaming operation and entering the interior cavity in the frame-like back where it fonns a core of soft foam.

7. A unit as defined in claim 1 including upholstery material superimposed on said soft foam and wherein nailing grooves are provided in the back and the seat, and wherein the center of the bottom region of the lateral narrow sides of the back is provided with recesses, the ends of the covering material, drawn onto these parts being inserted into the said grooves and recesses and secured therein.

8. A unit as defined in claim 1 wherein the top of the back is provided with narrow projections, said semi-rigid foam layer extending over said top of the back, whereby said projections improve the hold of the layer of semi-rigid foam.

9. A unit as defined in claim 1 including side panels, means joining said side panels along opposite sides of said seat element and said back element, said side panels having grooves provided in the top of the side panels and along the outsides of said side panels at a short distance below the top edge thereof, and in which an arm pad of semi-rigid foam said foam extending into said grooves to form tongues serving to secure the arm rest to the side panel.

10. A unit as defined in claim 1 wherein said back frame element of rigid foam is in the shape of an open ended U, the height of the U being lower than the height of the entire back, a tubular resilient element being inserted into the top end of the arms of the U to fonn a closed frame, said semi-rigid foam layer enclosing said resilient element and said back element to fonn a complete, closed back. 

1. A unit of upholstered seating furniture which includes a plurality of framing elements made from rigid foam and a plurality of upholstering elements made from soft foam wherein the improvement comprises: at least one opening defined in at least some of the framing elements, the surface of rigid foam around said opening being in a compressed condition, a layer of semi-rigid foam at least partly covering at least one framing element, said semi-rigid foam serving as both a base for the seat and back and as a resilient base for soft foam in other parts of said unit, said openings being provided with chamfered corners thereby reducing undesirable stress concentrations, at least a side of one of said opening and chamfered corners associated therewith extending obliquely to a surface of said framing elements, said base and back elements of said seat each having abutting oblique surfaces forming a joint surface, and at least one of said base and said back elements being tapered as to depth.
 2. A unit as defined in claim 1 wherein grooves are provided on the adjacent surfaces of said rigid foam elements, the open ends of said grooves abutting against one another and having cross section which narrows towards their open sides, said semi-rigid foam running into said grooves during foaming so as to form connection elements with said rigid foam elements.
 3. A unit as defined in claim 1 wherein a metal reinforcing profile is incorporated in the rigid foam element forming the seat and a metal reinforcing profile is incorporated in the rigid foam element forming the back and wherein the reinforcing profiles of the seat and the reinforcing profiles of the back include single flat bars, said bars being aligned with said joint surfaces, and including fastening means cooperating with said bars for securing said back and seat together at said joint surfaces.
 4. A unit as defined in claim 1 wherein the top surface of the front end of the seat is provided with respective recesses in order to provide the foamed-on layers with a greater thickness in the region where the seated person rests his legs, said semi-rigid foam layer having a substantially plane top surface extending across said recesses, whereby the layers of semi-rigid foam and the layers of soft foam being formed on in varying thicknesses according to the softness and resilience required at the respective places.
 5. A unit as defined in claim 1 wherein the resPective layers of semi-rigid foam foamed onto the seat and the back are provided with holes for the purpose of ventilation.
 6. A unit as defined in claim 1 wherein a layer of soft foam is foamed onto the layer of semi-rigid foam on the back, the soft foam flowing through the holes during the foaming operation and entering the interior cavity in the frame-like back where it forms a core of soft foam.
 7. A unit as defined in claim 1 including upholstery material superimposed on said soft foam and wherein nailing grooves are provided in the back and the seat, and wherein the center of the bottom region of the lateral narrow sides of the back is provided with recesses, the ends of the covering material, drawn onto these parts being inserted into the said grooves and recesses and secured therein.
 8. A unit as defined in claim 1 wherein the top of the back is provided with narrow projections, said semi-rigid foam layer extending over said top of the back, whereby said projections improve the hold of the layer of semi-rigid foam.
 9. A unit as defined in claim 1 including side panels, means joining said side panels along opposite sides of said seat element and said back element, said side panels having grooves provided in the top of the side panels and along the outsides of said side panels at a short distance below the top edge thereof, and in which an arm pad of semi-rigid foam said foam extending into said grooves to form tongues serving to secure the arm rest to the side panel.
 10. A unit as defined in claim 1 wherein said back frame element of rigid foam is in the shape of an open ended U, the height of the U being lower than the height of the entire back, a tubular resilient element being inserted into the top end of the arms of the U to form a closed frame, said semi-rigid foam layer enclosing said resilient element and said back element to form a complete, closed back. 